.animation {
  /* position: relative; */
  width: 100px;
  height: 100px;
  margin-left: 500px;
  background-color: steelblue;
  border-radius: 50%;
  box-shadow: 0 0 2px 1px burlywood;
  animation: move 5s linear 0s infinite;
}
/* 坐标的变动(0，0)->(500, 0)-> (500, 500)-> (0, 500)-> (0, 0) */
@keyframes move {
  0% {
    transform: translateX(0) translateY(0);
  }
  25% {
    transform: translateX(500px) translateY(0);
  }
  50% {
    transform: translateX(500px) translateY(500px);
  }
  75% {
    transform: translateX(0) translateY(500px);
  }
  100% {
    transform: translateX(0) translateY(0);
  }
}
